[Pw_forum] Convergence of relax of slab calculation
Mahya Zare
mahyazare68 at gmail.com
Thu Aug 6 18:28:51 CEST 2015
I want electronic and optical properties of cerium oxide do I check my
inputs to check the correct sheet is Nano?
On Thu, Aug 6, 2015 at 7:17 PM, Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>
wrote:
>
> Dear Ben Liew,
>
> If one is lucky, the system might converge to the right magnetic ground
> state with a "random guess". Yet if the system has several local minima, or
> the initial guess is very far from the true magnetic ordering, one might
> get very bad initial densities (total and spin density, or spin-up and
> spin-down densities), leading to difficulties in convergence and maybe even
> divergence. Yet-another-issue might be bad description of the electronic
> structure with the GGA's, I seem to remember that in the case of MnO2 the
> GGA gives reasonable results, even if the electronic band gap is naturally
> much too small (and using the smearing should help to get a convergence
> anyway).
>
> I would myself start by trying a weakly ferromagnetic guess (for example
> 'starting_magnetization(1) = 0.2' and seeing if something happens. If it
> converges, or doesn't, I would then see if an anti-ferromagnetic solution
> might also make sense (two types of Mn atoms in cell, etc).
>
> Greetings,
>
> apsi
>
>
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
> Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
> Ecole Normale Supérieure (ENS), Département de Chimie, Paris
> Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935
>
>
> On Wed, 5 Aug 2015, ben liew wrote:
>
> Dear Bahadir,
>> Thanks for your comments. I will try using a lower mixing_beta and change
>> the mixing_mode='local-TF'.
>>
>> Dear Ari Paavo Seitsonen,
>>
>> Thanks. I have no knowledge on the magnetism of my system. How could I
>> know
>> what value of starting_magnetization that I should use in my slab
>> calculation? Does the starting_magnetization affect the convergence of my
>> calculation?
>>
>> Thank you
>>
>>
>> Best Regards,
>> Ben Liew
>> Ph.D Student
>> Fuel Cell Institute,
>> The National University of Malaysia,
>> 43600 Bangi,
>> Selangor, Malaysia.
>> Contact no. : +6016 552 0878
>> Email : liewkienben at gmail.com
>>
>> On Wed, Aug 5, 2015 at 5:20 PM, Bahadır salmankurt <bsalmankurt at gmail.com
>> >
>> wrote:
>> Dear Ari P Seitsonen,
>> I didnt know that mixing_mode='local-TF' effect initial magnetic
>> moments. thanks for this. By the way, Do you know about e field
>> configuration? for example, for slab + molecule systems whose atomic
>> positions are in 0.5 and 0.65 along z direction , respectively, what
>> must values of the emaxpos and eopreg be?
>> Bests
>> Bahadir
>>
>> 2015-08-05 10:59 GMT+03:00 Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>:
>>
>> Dear Ben Liew,
>>
>> Without looking at the structure itself, adding to the
>> previous comment about the algorithm for mixing, you have
>> not really given any initial magnetic moments even if you
>> have 'nspin = 2': The 'starting_magnetization(1) = 0.0'
>> does not give any preferential spin ordering. Do you know
>> something about this, is the system expected to be
>> ferromagnetic, antiferromagnetic, ...?
>>
>> Tiny issues, I usually do the first calculation without
>> the surface dipole as it makes the convergence always a
>> bit trickier; and your
>> 'B ~= 2 * A', but you give the same number of k points in
>> both directions. (I usually tend to use smearing schemes
>> where the occupations are guaranteed to be in the physical
>> range of [0:1], but this is just a personal preference and
>> should thus be ignored)
>>
>> Greetings,
>>
>> apsi
>>
>>
>> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*
>> =-
>> Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi /
>> http://www.iki.fi/~apsi/
>> Ecole Normale Supérieure (ENS), Département de Chimie,
>> Paris
>> Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935
>>
>>
>> On Wed, 5 Aug 2015, ben liew wrote:
>>
>> Dear PWSCF users,
>>
>> Hi, I am a new user of Pwscf. I am working on
>> slab calculation for pyrolusite MnO2 (110)
>> surface with 3 atomic layers calculation and
>> fixed bottom 2 layers and only top atomic
>> layer is allowed to be relaxed. I have also
>> include the dipole correction for the
>> calculation to counteract with the interaction
>> between slabs. However, my calculation doesn't
>> seems to be converged as the scf accuracy is
>> not decreasing over each iteration. Below is
>> the estimated scf accuracy after hundreds of
>> iterations, it is not converging
>>
>> estimated scf accuracy <
>> 373.64728976 Ry
>> estimated scf accuracy <
>> 106.52177156 Ry
>> estimated scf accuracy <
>> 96.97567125 Ry
>> estimated scf accuracy <
>> 207.03807187 Ry
>> estimated scf accuracy <
>> 132.53045831 Ry
>> estimated scf accuracy <
>> 77.19101827 Ry
>> estimated scf accuracy <
>> 112.41885075 Ry
>> estimated scf accuracy <
>> 93.27430429 Ry
>> estimated scf accuracy <
>> 116.68049786 Ry
>> estimated scf accuracy <
>> 587.09711027 Ry
>> estimated scf accuracy <
>> 374.45312501 Ry
>> estimated scf accuracy <
>> 106.89811469 Ry
>> estimated scf accuracy <
>> 96.84898888 Ry
>> estimated scf accuracy <
>> 207.83006869 Ry
>> estimated scf accuracy <
>> 132.74588293 Ry
>> estimated scf accuracy <
>> 77.09445200 Ry
>> estimated scf accuracy <
>> 112.41688597 Ry
>> estimated scf accuracy <
>> 93.57796273 Ry
>> estimated scf accuracy <
>> 116.25663912 Ry
>> estimated scf accuracy <
>> 587.39968959 Ry
>> estimated scf accuracy <
>> 374.91438307 Ry
>> estimated scf accuracy <
>> 106.71641516 Ry
>> estimated scf accuracy <
>> 96.75392736 Ry
>>
>> I have include my input file as followed. Can
>> anyone tell me is that any problem with my
>> input file?
>>
>> &control
>> calculation = 'relax'
>> tstress=.true.
>> tprnfor=.true.
>>
>> pseudo_dir='/home/ben/Downloads/espresso-5.1.2/pseudo'
>> outdir='./vc3'
>> prefix='pyrolusite'
>> tefield=.true.
>> dipfield=.true.
>> /
>> &system
>> ibrav=8,
>> A=2.8563, B=6.2199, C=20.0
>> nat=18, ntyp=2,
>> starting_magnetization(1)=0.0
>> nspin=2
>> ecutwfc=37.0
>> ecutrho=250.0
>> occupations='smearing'
>> smearing='m-v'
>> degauss=0.01
>> edir=3
>> emaxpos=0.5
>> eopreg=0.1
>> eamp=0.001
>> /
>> &electrons
>> electron_maxstep=500
>> conv_thr=1.0d-6
>> mixing_beta=0.7
>> /
>> &ions
>> ion_dynamics='bfgs'
>> /
>> ATOMIC_SPECIES
>> Mn 54.9380 Mn.pbe-spn-kjpaw_psl.0.3.1.UPF
>> O 15.9994 O.pbe-kjpaw.UPF
>> ATOMIC_POSITIONS (angstrom)
>> O 1.428129 3.109734 0.000000 0 0
>> 0
>> O 1.428129 0.000241 0.652526 0 0
>> 0
>> Mn 1.428129 3.109896 1.883398 0 0
>> 0
>> O 0.000000 1.885646 1.883398 0 0
>> 0
>> O 0.000000 4.334118 1.883398 0 0
>> 0
>> Mn 0.000000 0.000062 1.883398 0 0
>> 0
>> O 0.000000 5.014614 4.987475 0 0
>> 0
>> O 0.000000 1.205401 4.987475 0 0
>> 0
>> Mn 0.000000 3.109816 4.987475 0 0
>> 0
>> Mn 1.428129 0.000027 4.987475 0 0
>> 0
>> O 1.428129 3.109734 3.767387 0 0
>> 0
>> O 1.428129 0.000241 3.114269 0 0
>> 0
>> O 1.428129 3.109734 6.207560
>> O 1.428129 0.000241 6.860698
>> Mn 1.428129 3.109896 8.091569
>> O 0.000000 1.885646 8.091569
>> O 0.000000 4.334118 8.091569
>> Mn 0.000000 0.000062 8.091569
>> K_POINTS (automatic)
>> 5 5 1 0 0 0
>>
>> Your comments and suggestion is much
>> appreciated.Thank you.
>>
>>
>> Best Regards,
>> Ben Liew
>> Ph.D Student
>> Fuel Cell Institute,
>> The National University of Malaysia,
>> 43600 Bangi,
>> Selangor, Malaysia.
>> Contact no. : +6016 552 0878
>> Email : liewkienben at gmail.com
>>
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>>
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>>
>>
>>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20150806/5c8da626/attachment.html>
More information about the users
mailing list